CN111869328A

CN111869328A - Dimmer interface with reduced power consumption

Info

Publication number: CN111869328A
Application number: CN201880087137.1A
Authority: CN
Inventors: 宋志华
Original assignee: Bright Sharp LLC
Current assignee: Bright Sharp LLC; Lumileds LLC
Priority date: 2017-12-20
Filing date: 2018-12-20
Publication date: 2020-10-30
Also published as: WO2019126584A1; TWI698153B; TW202118347A; TW201931949A; TWI771692B

Abstract

The disclosed subject matter includes an apparatus that includes a dimmer switch interface. The switch interface includes a transformer having a first winding magnetically coupled to a second winding, the first winding electrically coupled to a pair of terminals. The switching interface further includes a current source configured to provide an intermittent alternating current to the second winding, the intermittent alternating current having a periodic waveform, each period of the waveform including a first portion during which the current is fixed at a predetermined fixed low value and a second portion during which the current alternates between a high value and a low value.

Description

Dimmer interface with reduced power consumption

Background

Light emitting diodes ("LEDs") are commonly used as light sources in a variety of applications. LEDs are more energy efficient than traditional light sources, for example, providing much higher energy conversion efficiency than incandescent and fluorescent lamps. In addition, LEDs radiate less heat to the illuminated area and provide a greater range of control over brightness, emission color, and spectrum than traditional light sources. These characteristics make LEDs an excellent choice for a variety of lighting applications, from indoor lighting to automotive lighting. Accordingly, there is a need for improved LED-based illumination systems that take advantage of the advantages of LEDs to provide high quality illumination.

Disclosure of Invention

The present disclosure addresses this need. According to aspects of the present disclosure, there is disclosed a lighting system comprising: a lighting fixture comprising a driver coupled to a light source; a dimmer switch; and a dimmer switch interface, the dimmer switch interface comprising: (i) a transformer having a first winding magnetically coupled to a second winding, the first winding electrically coupled to the dimmer switch, and the second winding electrically coupled to a driver of the light fixture; and (ii) a current source configured to power the transformer with intermittent alternating current when the current source is energized.

Drawings

The drawings described below are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure. Like reference numerals shown in the drawings denote like parts in the various embodiments.

Fig. 1 is a schematic diagram of an example of a lighting system according to aspects of the present disclosure;

fig. 2 is a diagram of a current signal for driving a transformer in a dimmer switch interface of the lighting system of fig. 1, according to aspects of the present disclosure;

fig. 3 is a schematic diagram of another example of a lighting system according to aspects of the present disclosure;

fig. 4 is a diagram of a current signal for driving a transformer in a dimmer switch interface of the lighting system of fig. 3, according to aspects of the present disclosure;

Fig. 5 is a diagram of control signals for controlling operation of a current source in a dimmer switch interface of the lighting system of fig. 3, according to aspects of the present disclosure;

fig. 6 is a circuit diagram of an example of a current source that may be used in the dimmer switch interface of the lighting system of fig. 3, in accordance with aspects of the present disclosure;

fig. 7 is a flow chart of an example of a process performed by a controller that is part of the dimmer switch interface of the lighting system of fig. 3, in accordance with aspects of the present disclosure;

fig. 8 is a diagram showing a control signal and a corresponding current signal that may be generated by a current source in a dimmer switch interface of the lighting system of fig. 3, in accordance with aspects of the present disclosure;

fig. 9 is a diagram showing another control signal and another corresponding current signal that may be generated by a current source in a dimmer switch interface of the lighting system of fig. 3, in accordance with aspects of the present disclosure;

FIG. 10 is a top view of an electronics board for an integrated LED lighting system according to one embodiment;

FIG. 11A is a top view of an electronics board with an array of LEDs attached to a substrate at LED device attachment regions in one embodiment;

FIG. 11B is a diagram of one embodiment of a dual channel integrated LED illumination system having electronic components mounted on both surfaces of a circuit board;

FIG. 11C is a schematic diagram of an embodiment of an LED lighting system in which the LED array is located on an electronics board separate from the driver and control circuitry;

fig. 11D is a block diagram of an LED lighting system with an array of LEDs and some electronics on an electronics board separate from the driver circuit;

fig. 11E is a diagram of an example LED lighting system showing a multi-channel LED driver circuit;

FIG. 12 is a diagram of an example application system;

fig. 13A is a diagram showing an LED device; and

fig. 13B is a diagram illustrating a plurality of LED devices.

Detailed Description

Examples of different light illumination system and/or light emitting diode ("LED") embodiments are described more fully below with reference to the accompanying drawings. These examples are not mutually exclusive and features found in one example may be combined with features found in one or more other examples to achieve further implementations. Thus, it will be understood that the examples shown in the figures are provided for illustrative purposes only and are not intended to limit the present disclosure in any way. Like reference numerals refer to like elements throughout.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, a first element could be termed a second element, and a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term "and/or" can include any and all combinations of one or more of the associated listed items.

It will be understood that when an element such as a layer, region or substrate is referred to as being "on" or extending "onto" another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there may be no intervening elements present. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element and/or be connected or coupled to the other element via one or more intermediate elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present between the element and the other element. It will be understood that these terms are intended to encompass different orientations of the elements in addition to any orientation depicted in the figures.

Relative terms, such as "below," "above," "upper," "lower," "horizontal," or "vertical," may be used herein to describe one element, layer or region's relationship to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

Further, whether the LEDs, LED arrays, electrical components, and/or electronic components are housed on one, two, or more electronics boards may also depend on design constraints and/or applications.

Semiconductor Light Emitting Devices (LEDs) or optical power emitting devices, such as devices that emit Ultraviolet (UV) or Infrared (IR) optical power, are among the most efficient light sources currently available. These devices (hereinafter "LEDs") may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, edge emitting lasers, and the like. For example, LEDs may be attractive candidates for many different applications due to their compact size and lower power requirements. For example, they may be used as light sources (e.g., flash and camera flash) for hand-held battery-powered devices (e.g., cameras and cell phones). They may also be used, for example, for automotive lighting, head-up display (HUD) lighting, horticulture lighting, street lighting, video flashlights, general lighting (e.g., home, shop, office and studio lighting, theater/stage lighting, and architectural lighting), Augmented Reality (AR) lighting, Virtual Reality (VR) lighting, backlighting as a display, and IR spectroscopy. A single LED may provide light at a lower brightness than an incandescent light source, and thus a multi-junction device or LED array (such as a monolithic LED array, a micro LED array, etc.) may be used in applications where higher brightness is desired or needed.

A dimmer switch is a device used to control the intensity of light produced by a light fixture. Externally, a manually operated dimmer switch may appear as a knob that a user may turn to increase or decrease the brightness of the light fixture. Internally, the dimmer switch may include a variable resistor coupled to a knob. The variable resistor may be used to adjust the value of the voltage signal provided to the light fixture by the dimmer switch.

One type of dimming system often used for fluorescent lamps and LED lighting is known as 0-10V dimming. According to this system, the voltage signal supplied to the lamp by the 0-10V dimmer switch varies between 0V and 10V. When the value of the voltage signal is below a certain threshold close to 0V, the luminaire may operate at its lowest possible brightness or turn itself off completely. When the value of the voltage signal is above a certain threshold near 10V, the luminaire may operate at its maximum brightness.

When using a 0-10V system, the dimmer switch is typically connected to the light source via a dimmer switch interface. A dimmer switch interface is a device that may be inserted between a dimmer switch and a light fixture to electrically isolate the dimmer switch and suppress noise. To accomplish this function, the dimmer switch interface may include a transformer for driving the dimmer switch and connecting the dimmer switch to the light fixture.

One drawback of dimmer switch interfaces is that they are typically energy inefficient. A typical dimmer switch interface may typically consume 100mW or more of power, primarily due to the transformer in the dimmer switch interface. Such consumption may be undesirable because it may increase the cost of operating the dimmer switch interface. Furthermore, power consumption due to the transformer in the dimmer switch interface may prevent a lighting system utilizing the dimmer switch interface from complying with various current and future environmental regulations that require limiting the standby power of the lighting system.

According to aspects of the present disclosure, a dimmer switch interface with reduced power consumption is disclosed. The dimmer switch interface may include a transformer for magnetically coupling the dimmer switch to the light fixture. The transformer may be driven by a current source configured to provide an intermittent current to the transformer. When the transformer is driven by an intermittent current, the current supplied to the transformer is switched between a high current value (e.g., 10 mA) and a low current value (e.g., 0A). During the period in which the intermittent current is switched to a low value (e.g., 0A), the transformer is turned off and does not consume any power. Therefore, when the transformer is driven using an intermittent current, power consumption of the transformer can be significantly reduced.

According to aspects of the present disclosure, a dimmer switch interface is disclosed, comprising: a pair of first terminals for connecting the dimmer switch interface to the dimmer switch; a pair of second terminals for connecting the dimmer switch to a driver of a light fixture; a transformer having a first winding magnetically coupled to a second winding, the first winding being electrically coupled to the pair of first terminals and the second winding being electrically coupled to the pair of second terminals; and a current source configured to power the transformer with intermittent alternating current when the current source is energized.

According to aspects of the present disclosure, an apparatus is disclosed, comprising: a driver for the light fixture; and a dimmer switch interface for connecting the driver to the dimmer switch, the dimmer switch interface comprising: (i) a transformer having a first winding magnetically coupled to a second winding, the first winding being electrically coupled to a pair of terminals for connecting the dimmer switch interface to the dimmer switch, and the second winding being electrically coupled to the driver; and (ii) a current source configured to power the transformer with intermittent alternating current when the current source is energized.

Fig. 1 is a diagram of an example of a lighting system 100, according to aspects of the present disclosure. The lighting system 100 may include a dimmer switch 110, a light fixture 120, and a dimmer switch interface 130 coupling the dimmer switch 110 to the light fixture 120.

The dimmer switch 110 may be a 0-10V dimmer switch and/or any other suitable type of dimmer switch. The dimmer switch 110 may include a variable resistor (e.g., a potentiometer) and/or any suitable type of device capable of placing a variable load between the terminals T1 of the dimmer switch interface 130. Additionally or alternatively, the dimmer switch 110 may include any suitable type of semiconductor device capable of varying the voltage between the terminals T1 of the dimmer switch interface 130. Briefly, in accordance with aspects of the present disclosure, the dimmer switch 110 may be any suitable type of device capable of generating a voltage signal indicative of a desired brightness level of light output from the light fixture 120.

In some implementations, the dimmer switch 110 can include a light sensor configured to measure a level of ambient light near the light fixture 120 and generate a voltage signal based on the measured level of ambient light. Additionally or alternatively, in some embodiments, the dimmer switch 110 may include a knob or slider that may be used to actuate a potentiometer that is part of the dimmer switch 110. Additionally or alternatively, the dimmer switch 110 may include a wireless receiver (e.g., a ZigBee gateway, WiFi receiver, remote control receiver, etc.) capable of receiving an indication of a desired brightness level from a remote device (e.g., a user's smartphone or remote control) and generating a corresponding voltage signal based on the indication.

Light fixtures 120 may include any suitable type of light fixture. Light fixture 120 may include a driver 122 and a light source 124 powered using signal PWR. Light source 124 may include any suitable type of light source, such as a fluorescent light source, an incandescent light source, and/or one or more Light Emitting Diodes (LEDs). In this example, the light source 124 includes one or more LEDs, and the signal PWR is a DC or Pulse Width Modulated (PWM) signal generated by the driver 122 based on the signal DIM received by the driver 122 from the dimmer switch interface 130. Driver 122 may include a DC/DC converter circuit, a tuning engine, and the like.

The signal DIM may be a voltage signal. The level of signal DIM may determine the DC amplitude and/or duty cycle of signal PWR. If signal DIM has a first level (e.g., 2V), driver 122 may apply a first DC amplitude and/or a first duty cycle on signal PWR. Conversely, if signal DIM has a second level (e.g., 5V), driver 122 may apply a second DC magnitude and/or second duty cycle on signal PWR that is different from the DC magnitude and/or duty cycle of the first DIM level. As can be readily appreciated, the DC amplitude and/or duty cycle of the signal PWR determines the amount of current delivered to the light source 124, which in turn may determine the brightness of the light output from the light source 124.

The dimmer switch interface 130 may provide isolation between the light fixture 120 and the dimmer switch 110, primarily for protecting a person operating the dimmer switch from electrical shock. The dimmer switch interface 130 may include a converter circuit 132 coupled to a converter circuit 134 via a transformer 136. The transformer 136 may be driven with a continuous current signal S0 generated by the current source 138. As shown in fig. 2, signal S0 may be an Alternating Current (AC) signal and may be shaped as a continuous square wave. However, in alternative embodiments, signal S0 may be shaped as a sine wave and/or any other suitable type of wave. In some embodiments, the current signal may be continuous when the current signal has a constant current level.

Transformer 136 may include winding W1 and winding W2 magnetically coupled to winding W1. Winding W1 may be electrically coupled to light fixture 120 (e.g., via converter circuit 132). The winding W2 may be electrically coupled (e.g., via the converter circuit 134) to the dimmer switch 110. In some implementations, the winding W2 may be electrically coupled (e.g., via the converter circuit 134) to the terminal T1 of the dimmer switch interface 130. In this case, the dimmer switch 110 may also be coupled to the terminal T1 to complete the electrical connection between the dimmer switch 110 and the winding W2. Additionally or alternatively, in some embodiments, winding W1 may be electrically coupled (e.g., via converter circuit 132) to terminal T2 of dimmer switch interface 130. In this case, the driver 122 may also be coupled to the terminal T2 of the dimmer switch interface 130 to receive a signal DIM for controlling the brightness of the light source 124.

In operation, the winding W2 carries dimming control information from the dimmer switch 110 via the converter circuit 134, the converter circuit 134 also converting the voltage across the winding W2 to a DC current to power the dimmer switch 110. As described above, the voltage across winding W2 may be generated, at least in part, by dimmer switch 110. In addition, the voltage across winding W2 may be transmitted to winding W1 of transformer 136 by magnetic coupling and converted to a DC current by converter circuit 132 to generate voltage signal DIM. The voltage signal DIM may then be used by the driver 122 of the luminaire 120 to adjust the brightness of the luminaire 120. According to aspects of the present disclosure, the converter circuit 132 may include any suitable electronic circuit configured to generate a DC signal based on an AC signal received from the winding W1. Further, according to aspects of the present disclosure, converter circuit 134 may include any suitable electronic circuit configured to form a desired AC signal on winding W2.

Fig. 3 is an illustration of an example of a lighting system 300 with improved power consumption. As discussed further below, improved power consumption is achieved by using a current source that intermittently turns on and off a transformer in a dimmer switch interface of the system in order to reduce the amount of power consumed to drive the transformer. According to the example of fig. 3, the lighting system 300 may include a dimmer switch 310, a light fixture 320, and a dimmer switch interface 330 coupling the dimmer switch 310 to the light fixture 320.

The dimmer switch 310 may be a 0-10V dimmer switch and/or any other suitable type of dimmer switch. The dimmer switch 310 may include a variable resistor (e.g., a potentiometer), and/or any suitable type of device capable of placing a variable load between the terminals T1 of the dimmer switch interface 330. Additionally or alternatively, the dimmer switch 310 may include any suitable type of semiconductor device capable of varying the voltage between the terminals T1 of the dimmer switch interface 330. Briefly, in accordance with aspects of the present disclosure, the dimmer switch 310 may be any suitable type of device capable of generating a voltage signal indicative of a desired brightness level of light output from the light fixture 320.

In some implementations, the dimmer switch 310 can include a light sensor configured to measure a level of ambient light near the light fixture 320 and generate a voltage signal based on the measured level of ambient light. Additionally or alternatively, in some embodiments, the dimmer switch 310 may include a knob or slider that may be used to actuate a potentiometer that is part of the dimmer switch 310. Additionally or alternatively, the dimmer switch 310 may include a wireless receiver (e.g., a ZigBee gateway, WiFi receiver, remote control receiver, etc.) capable of receiving an indication of a desired brightness level from a remote device (e.g., a user's smartphone or remote control) and generating a corresponding voltage signal based on the indication.

The light fixtures 320 may include any suitable type of light fixture. Light fixture 320 may include a driver 322 and a light source 324 powered using signal PWR. The light source 324 may include any suitable type of light source, such as a fluorescent light source, an incandescent light source, and/or one or more Light Emitting Diodes (LEDs). In this example, the light source 324 includes one or more LEDs, and the signal PWR is a DC or pulse width modulated signal generated by the driver 322 based on the signal DIM received by the driver 322 from the dimmer switch interface 330.

The signal DIM may be a voltage signal. The level of signal DIM may determine the DC amplitude and/or duty cycle of signal PWR. If signal DIM has a first level (e.g., 2V), driver 322 may apply a first DC amplitude and/or a first duty cycle on signal PWR. Conversely, if signal DIM has a second level (e.g., 5V), driver 322 may apply a second DC magnitude and/or second duty cycle on signal PWR that is different from the DC magnitude and/or duty cycle of the first DIM level. As can be readily appreciated, the DC amplitude and/or duty cycle of the signal PWR determines the amount of current delivered to the light source 324, which in turn may determine the brightness of the light output from the light source 324.

The dimmer switch interface 330 may provide isolation between the light fixture 320 and the dimmer switch 310, primarily for protecting a person operating the dimmer switch from electrical shock. The dimmer switch interface 330 may include a converter circuit 332 coupled to a converter circuit 334 via a transformer 336. The transformer 336 may be driven with an intermittent current signal S1 generated by a current source 338. The operation of the current source 338 and the waveform of the intermittent current signal S1 will be discussed in further detail below.

Transformer 336 may include winding W1 and winding W2 magnetically coupled to winding W1. Winding W1 may be electrically coupled to light fixture 320 (e.g., via converter circuit 332). Winding W2 may be electrically coupled to dimmer switch 310 (e.g., via converter circuit 334). In some implementations, the winding W2 may be electrically coupled (e.g., via the converter circuit 334) to the terminal T1 of the dimmer switch interface 330. In this case, the dimmer switch 310 may also be coupled to terminal T1 to complete the electrical connection between the dimmer switch 310 and the winding W2. Additionally or alternatively, in some embodiments, winding W1 may be electrically coupled (e.g., via converter circuit 332) to terminal T2 of dimmer switch interface 330. In this case, the driver 322 may also be coupled to the terminal T2 of the dimmer switch interface 330 to receive a signal DIM for controlling the brightness of the light source 324.

In operation, the winding W2 carries dimming control information from the dimmer switch 310 via the converter circuit 334, the converter circuit 334 also converting the voltage across the winding W2 to a DC current to power the dimmer switch 310. As described above, the voltage across winding W2 may be generated, at least in part, by dimmer switch 310. In addition, the voltage across winding W2 may be transmitted to winding W1 of transformer 336 by magnetic coupling and converted to voltage signal DIM by converter circuit 332. The voltage signal DIM may then be used by the driver 322 of the light fixture 320 to adjust the brightness of the light fixture 320. According to aspects of the present disclosure, converter circuit 332 may include any suitable electronic circuit configured to generate a DC signal based on an AC signal received from winding W1. Further, according to aspects of the present disclosure, converter circuit 334 may include any suitable electronic circuit configured to form a desired AC signal on winding W2.

As described above, the current source 338 may power the transformer 336 with the intermittent current signal S1. The signal S1 may be an alternating current signal. As shown in fig. 4, the signal S1 may be cyclic in nature. Each cycle 419 of signal S1 may include a portion 413 during which signal S1 has a first current level and a portion 417 during which signal S1 has a second current level. The second current level may be higher than the first current level. For example, in some embodiments, the first current level may be 0A, and the second current level may have any value greater than 0A.

The frequency at which the signal S1 switches to the second current level may be referred to as the pulse frequency. In some embodiments, signal S1 may have a pulse frequency of 1 Hz. However, alternative embodiments are possible in which signal S1 has any suitable frequency (e.g., 5Hz, 10Hz, 0.5Hz, etc.).

When the signal S1 is at the first current level, the transformer 336 may be turned off (or operated in a reduced power consumption mode). When the signal S1 is at the second current level, the transformer 336 may be turned on and/or operated in a normal power consumption mode. In some embodiments, current source 338 may intermittently turn transformer 336 on and off by driving transformer 336 with an intermittent current signal. This, in turn, may cause the transformer 336 to be powered only a portion of the time the dimmer switch interface 330 is energized (or in use), resulting in reduced power consumption.

In some embodiments, the signal S1 may be a PWM signal generated by intermittently varying its duty cycle. For example, during portion 413 of each cycle 419, current source 338 may switch the duty cycle of signal S1 to a first value (e.g., 0%). As another example, during portion 417 of each cycle 419, current source 338 may switch the duty cycle of signal S1 to a second value (e.g., 50%) that is greater than the first value.

The duration of each cycle 419 of the signal S1 may determine the response time of the dimmer switch 310. As described above, in some embodiments, the duration of each period 419 may be 1 second. In this case, the duration of each portion 413 of period 419 may be 900ms, and the duration of each portion 417 of period 419 may be 100 ms. Alternatively, in some embodiments, the duration of each portion 413 may be 980ms and the duration of each portion 417 may be 20 ms. In short, the present disclosure is not limited to any particular duration of portions 413 and 417 and/or period 419.

In some embodiments, the signal S1 may be generated based on the control signal CTRL provided by the control circuit 340 to the current source 338. Control circuit 340 may include any suitable type of control circuit. For example, in some embodiments, the control circuit may be a square wave generator and/or other type of signal generator. Additionally or alternatively, in some embodiments, the control circuit 340 may be a low power processor and/or a general purpose processor (e.g., an ARM based processor) capable of performing logical operations such as comparisons and branches. Additionally or alternatively, in some embodiments, the control circuit 340 may comprise a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). Additionally or alternatively, in some embodiments, the control circuitry 340 may be configured to execute one or more processor-executable instructions that, when executed by the control circuitry 340, cause the control circuitry 340 to perform a process 700, which is discussed further below with reference to fig. 7. The processor-executable instructions may be stored in a memory (not shown) that is part of the dimmer switch interface 330 and/or the control circuit 340. Additionally or alternatively, the processor-executable instructions may be stored in a non-transitory computer-readable medium, such as a Secure Digital (SD) card. Although the control circuit 340 and the current source 338 are described as separate elements, it will be understood that alternative implementations are possible in which the control circuit 340 and the current source 338 are integrated with each other.

As shown in fig. 5, the control signal CTRL may be a DC square wave having a period 510. Each cycle 510 may have a portion 512 and a portion 514, with the signal CTRL having a first duty cycle in the portion 512 and a second duty cycle in the portion 514 that is greater than the first duty cycle. For example, in some embodiments, the first duty cycle may be 0% and the second duty cycle may be 50%. In some embodiments, each portion 512 of the control signal CTRL may have the same duration as each portion 413 of the current signal S1. Additionally or alternatively, in some embodiments, each portion 514 of the control signal CTRL may have the same duration as each portion 417 of the current signal S1. The manner in which the control signal CTRL is used to generate the current signal S1 will be discussed further below with reference to fig. 6.

Fig. 6 is a diagram illustrating the internal structure of the current source 338 in further detail, according to aspects of the present disclosure. As shown, the current source 338 may include a DC voltage source V1 and a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Q3. The control signal CTRL generated by the control circuit 340 may be applied to the gate of the MOSFET Q3. The drain of the MOSFET Q3 may be coupled to the respective bases of an NPN transistor Q1 and a PNP transistor Q2. Further, the collector of the transistor Q1 may be coupled to the positive terminal (e.g., + 12V) of the voltage source V1, and the collector of the transistor Q2 may be coupled to the negative terminal (e.g., 0V) of the voltage source V1. The emitters of transistors Q1 and Q2 may be coupled to each other at node N3. As shown, a resistor R5 and a capacitor C4 may be coupled in series to the node N3.

MOSFET Q3 may be turned on when signal CTRL is high and turned off when signal CTRL is low. When the MOSFET Q3 is off, the resistor R4 may forward bias the NPN transistor Q1 and reverse bias the PNP transistor Q2, thereby turning on the NPN transistor Q1 and turning off the PNP transistor Q2. When the transistor Q1 is turned on and the PNP transistor Q2 is opened, a high voltage near the positive terminal voltage of V1 (e.g., + 12V) may appear at node N3 due to the electrical path between the positive terminal across the voltage source V1 and node N3 becoming closed. When the MOSFET Q3 is turned on, the common base of transistors Q1 and Q2 is pulled down, thereby turning off the NPN transistor Q1 and turning on the PNP transistor Q2. When transistor Q1 is open and PNP transistor Q2 is conductive, a low voltage near the negative terminal voltage of V1 (e.g., 0V) may appear at node N3 due to the electrical path between the negative terminal across voltage source V1 and node N3 becoming closed. In other words, by applying the signal CTRL at the gate of the MOSFET Q3, the control circuit 340 may cause a square wave DC voltage at the frequency of the control signal CTRL to appear at the node N3. The capacitor C4 can block the DC component of the DC square wave, turning it into a square wave AC voltage wave.

According to the example discussed with reference to fig. 3-6, the current source 338 may be configured to always supply the transformer 336 with intermittent current. However, alternative embodiments are possible in which the current source 338 is configured to provide intermittent current to the transformer 336 only when the dimmer switch 310 is in the standby mode. In this case, the current source 338 may be configured to provide a continuous current to the transformer 336 when the dimmer switch 310 is not in the standby mode.

According to aspects of the present disclosure, the dimmer switch 310 may be in a standby mode when it generates a voltage signal (e.g., 0V, 10V, etc.) such that the driver 322 completely turns off the light source 324 (e.g., by cutting off the current supply to the light source 324). Additionally or alternatively, the dimmer switch 310 may be considered to be in the standby mode when the dimmer switch 310 generates a voltage signal that is less than (or greater than) a predetermined threshold. For example, a manually operated dimmer switch may be in a standby mode when a knob on the dimmer switch is rotated all the way in one direction.

According to aspects of the present disclosure, being able to provide intermittent current to the transformer 336 when the dimmer switch 310 is in the standby mode may help improve the energy efficiency of the lighting system 300. For example, in some embodiments, switching transformer 336 with an intermittent current source having a 10% duty cycle may reduce power consumption by 90%. This reduction may be significant in jurisdictions that require the lighting system 300 to comply with laws and regulations that impose strict standby power limits on the lighting system.

Fig. 7 is a flow chart of an example of a process 700 for selectively switching a transformer with an intermittent current source when the dimmer switch 310 is placed in a standby mode according to aspects of the present disclosure.

In step 710, the control circuit 340 detects the voltage level of the signal DIM. In some embodiments, the control circuit 340 may detect the voltage level of the signal DIM by sampling the signal DIM using an analog-to-digital converter.

In step 720, the control circuit 340 detects whether the dimmer switch 310 is in the standby mode based on the level of the signal DIM. In some embodiments, the control circuit 340 may compare the level of the signal DIM with a predetermined threshold to detect whether the dimmer switch 310 is in the standby mode. According to a specific example, when the level of the signal DIM is below the threshold, the control circuit 340 may detect that the dimmer switch 310 is in the standby mode and proceed to step 740. According to the same example, when the level of the signal DIM is above the threshold, the control circuit 340 may detect that the dimmer switch 310 is not in the standby mode and proceed to step 730. Although in the present example the control circuit 340 detects that the dimmer switch 310 is in the standby mode when the level of the signal DIM is below the threshold, alternative embodiments are possible in which the control circuit 340 detects that the dimmer switch 310 is in the standby mode when the level of the signal DIM is above the threshold.

At step 730, the control circuit 340 provides a continuous current to the transformer 336. To provide intermittent current to the transformer 336, the control circuit 340 may provide a first control signal to the current source 338 that causes the current source 338 to output a continuous current. More specifically, the control circuit 340 may generate the control signal 810 as shown in FIG. 8. As shown, the control signal 810 may be a square wave with a constant duty cycle. When the control signal 810 is provided to the current source 338, the current source 338 may generate a continuous alternating current signal 820. As shown in fig. 8, the current signal 820 may be the same as or similar to the signal S0 discussed above with reference to fig. 2.

At step 740, control circuit 340 provides an intermittent current to transformer 336. To provide a continuous current to the transformer 336, the control circuit 340 may provide a second control signal to the current source 338 that causes the current source to output an intermittent current. More specifically, the control circuit 340 may provide a control signal 910, as shown in fig. 9, to the current source 338. As shown, the control signal 910 may be the same as or similar to the control signal CTRL discussed above with reference to fig. 3-6. When control signal 910 is provided to current source 338, current source 338 may output an intermittent alternating current signal 920, also shown in fig. 9, to transformer 336. As shown, the alternating current signal 920 may be the same as or similar to the signal S1 discussed above with reference to fig. 3-6.

Fig. 1-9 are provided as examples only. At least some of the elements discussed with reference to these figures may be arranged in a different order, combined, and/or omitted entirely. For example, although in the example of fig. 6, the transistors Q1 and Q2 are switched by MOSFET transistors, alternative embodiments are possible in which any other suitable type of switching device is used instead, such as solid state relays, PMOS transistors, and the like. Further, although in the present example PNP and NPN transistors are used to close different electrical paths between the voltage source V1 of the current source 338, alternative embodiments are possible in which any other suitable type of switching device, such as a solid state relay, PMOS transistor, etc., is used instead. Voltage source V1 may include any suitable type of voltage. For example, the voltage source may be a power connector. As another example, the voltage source may be a power adapter configured to convert an AC mains voltage to a DC voltage. Although the dimmer switch interface 330 and the driver 322 are shown as separate elements, it should be understood that the dimmer switch interface 330 and the driver 322 may in fact typically be integrated with each other.

Fig. 10 is a top view of an electronics board 311 for an integrated LED lighting system according to an embodiment. In alternative embodiments, two or more electronics boards may be used for the LED lighting system. For example, the LED array may be on a separate electronics board, or the sensor module may be on a separate electronics board. In the example shown, the electronics board 311 includes a power module 312, a sensor module 314, a connection and control module 316, and an LED attachment region 318 reserved for attaching an LED array to a substrate 321. The dimmer switch interface 330 of fig. 3 may be part of the power module 312 or may be external to the electronics board 311 and may provide an input to the power module 312.

Substrate 321 may be any board capable of mechanically supporting and providing electrical coupling to electrical components, electronic components, and/or electronic modules using conductive connections, such as tracks, traces, pads, vias, and/or wires. The substrate 321 may include one or more metallization layers disposed between or over one or more layers of non-conductive material, such as a dielectric composite. The power module 312 may include electrical and/or electronic components. In an example embodiment, the power module 312 includes an AC/DC conversion circuit, a DC/DC conversion circuit, a dimming circuit, and an LED driving circuit.

The sensor module 314 may include sensors as needed to implement the application of the LED array. Example sensors may include optical sensors (e.g., IR sensors and image sensors), motion sensors, thermal sensors, mechanical sensors, proximity sensors, or even timers. For example, LEDs in street lighting, general lighting, and horticulture lighting applications may be turned off/on and/or adjusted based on a number of different sensor inputs such as detected presence of a user, detected ambient lighting conditions, detected weather conditions, or based on time of day/night. This may include, for example, adjusting the intensity of the light output, the shape of the light output, the color of the light output, and/or turning the light on or off to conserve energy. For AR/VR applications, a motion sensor may be used to detect user motion. The motion sensor itself may be an LED, such as an IR detector LED. As another example, for camera flash applications, images and/or other optical sensors or pixels may be used to measure the illumination of a scene to be captured, such that the flash illumination color, intensity illumination pattern, and/or shape may be optimally calibrated. In an alternative embodiment, the electronics board 311 does not include a sensor module.

The connection and control module 316 may include a system microcontroller and any type of wired or wireless module configured to receive control inputs from external devices. By way of example, the wireless module may include Bluetooth, Zigbee, Z-Wave, Mesh, WiFi, Near Field Communication (NFC), and/or may use a peer-to-peer module. The microcontroller may be any type of special purpose computer or processor that may be embedded in the LED lighting system and configured or configurable to receive input (such as sensor data and data fed back from the LED module) from wired or wireless modules or other modules in the LED system and provide control signals to the other modules based thereon. The microcontroller may be part of the control circuit 340 of fig. 3 or may include the control circuit 340, as disclosed herein. The algorithms implemented by the special purpose processor may be implemented in a computer program, software, or firmware incorporated in a non-transitory computer readable storage medium for execution by the special purpose processor. Examples of non-transitory computer readable storage media include Read Only Memory (ROM), Random Access Memory (RAM), registers, cache memory, and semiconductor memory devices. The memory may be included as part of the microcontroller or may be implemented elsewhere, either on the electronics board 311 or external to the electronics board 311.

As used herein, the term module may refer to electrical and/or electronic components disposed on a separate circuit board that may be soldered to one or more electronics boards 311. However, the term module may also refer to electrical and/or electronic components that provide similar functionality, but which may be individually soldered to one or more circuit boards in the same area or in different areas.

Fig. 11A is a top view of the electronics board 311 in an embodiment where the LED array 410 is attached to the substrate 321 at the LED device attachment regions 318. The electronics board 311 together with the LED array 410 represent the LED lighting system 400A. Additionally, the power module 312 receives a voltage input at Vin 497 and a control signal from the connection and control module 316 through trace 418B and provides a drive signal to the LED array 410 through trace 418A. The LED array 410 is turned on and off by a driving signal from the power module 312. In the embodiment shown in FIG. 11A, connection and control module 316 receives sensor signals from sensor module 314 via trace 418C.

Figure 11B illustrates one embodiment of a dual channel integrated LED lighting system with electronic components mounted on both surfaces of circuit board 499. As shown in fig. 11B, the LED lighting system 400B includes a first surface 445A having inputs to receive the dimmer signal and the AC power signal and an AC/DC converter circuit 412 mounted on the first surface 445A. The LED system 400B includes a second surface 445B having a dimmer interface circuit 415, DC-

DC converter circuits

440A and 440B, a connection and control module 416 (a wireless module in this example) having a microcontroller 472, and an LED array 410 mounted on the second surface 445B. The LED array 410 is driven by two independent channels 411A and 411B. In alternative embodiments, a single channel may be used to provide the drive signal to the LED array, or any number of multiple channels may be used to provide the drive signal to the LED array. For example, fig. 11E shows an LED illumination system 400D with 3 channels, and is described in further detail below. The dimmer switch interface 330 of fig. 3 may be part of the dimmer interface circuit 415 and may provide an input to the microcontroller 472.

The LED array 410 may include two sets of LED devices. In an example embodiment, the LED devices of group A are electrically coupled to first lane 411A and the LED devices of group B are electrically coupled to second lane 411B. Each of the two DC-

DC converters

440A and 440B may provide a respective drive current for driving a respective LED group a and LED group B in the LED array 410 via a single channel 411A and 411B, respectively. The LEDs in one of the LED groups may be configured to emit light having a different color point than the LEDs in the second group of LEDs. By controlling the current and/or duty cycle applied by the individual DC/

DC converter circuits

440A and 440B via the individual channels 411A and 411B, respectively, the control of the composite color point of the light emitted by the LED array 410 can be adjusted within a range. Although the embodiment shown in fig. 11B does not include a sensor module (as described in fig. 10 and 11A), alternative embodiments may include a sensor module.

The illustrated LED lighting system 400B is an integrated system in which the LED array 410 and circuitry for operating the LED array 410 are provided on a single electronics board. Connections between modules on the same surface of circuit board 499 may be electrically coupled for exchanging, for example, voltage, current, and control signals between modules through surface or sub-surface interconnects (e.g., traces 431, 432, 433, 434, and 435) or metallization (not shown). Connections between modules on opposite surfaces of circuit board 499 may be electrically coupled through-board interconnects such as vias and metallization (not shown).

Fig. 11C shows an embodiment of an LED lighting system where the LED array is located on an electronics board separate from the driver and control circuitry. The LED lighting system 400C includes a power module 452 on an electronics board separate from the LED module 490. The power module 452 may include the AC/DC converter circuit 412, the sensor module 414, the connection and control module 416, the dimmer interface circuit 415, and the DC/DC converter 440 on the first electronics board. The LED module 490 may include embedded LED calibration and setting data 493 and an LED array 410 on a second electronics board. Data, control signals, and/or LED driver input signals 485 may be exchanged between the power module 452 and the LED module 490 via wiring, which may electrically and communicatively couple the two modules. Embedded LED calibration and setting data 493 may include any data needed by other modules within a given LED lighting system to control how LEDs in an LED array are driven. In one embodiment, the embedded calibration and setting data 493 may include data required by the microcontroller to generate or modify a control signal instructing the driver to provide power to each of LED group a and LED group B using, for example, a Pulse Width Modulation (PWM) signal. In this example, the calibration and setting data 493 may inform the microcontroller 472 about, for example, the number of power channels to be used, the desired color point of the composite light to be provided by the entire LED array 410, and/or the percentage of power provided by the AC/DC converter circuit 412 to be provided to each channel. As disclosed herein, the dimmer switch interface 330 of fig. 3 may be part of the dimmer interface circuit 415.

Fig. 11D shows a block diagram of an LED lighting system with an array of LEDs on an electronics board separate from the driver circuit, and some electronics. The LED system 400D includes a power conversion module 483 and an LED module 481 on separate electronics boards. The power conversion module 483 can include the AC/DC converter circuit 412, the dimmer interface circuit 415, and the DC-DC converter circuit 440, and the LED module 481 can include embedded LED calibration and setting data 493, the LED array 410, the sensor module 414, and the connection and control module 416. The power conversion module 483 can provide the LED driver input signal 485 to the LED array 410 via a wired connection between the two electronics boards.

Fig. 11E is a diagram of an example LED lighting system 400D showing a multi-channel LED driver circuit. In the illustrated example, the system 400D includes a power module 452 and an LED module 481 that includes embedded LED calibration and setting data 493 and three sets of

LEDs

494A, 494B, and 494C. Although three sets of LEDs are shown in FIG. 11E, one of ordinary skill in the art will recognize that any number of sets of LEDs may be used consistent with the embodiments described herein. Further, while the individual LEDs within each group are arranged in series, they may be arranged in parallel in some embodiments.

The LED array 491 may include groups of LEDs that provide light having different color points. For example, the LED array 491 may include a warm white light source via the first LED group 494A, a cool white light source via the second LED group 494B, and a neutral white light source via the third LED group 494C. The warm white light source via the first LED group 494A may include one or more LEDs configured to provide white light having a Correlated Color Temperature (CCT) of about 2700K. The cool white light source via the second LED group 494B may include one or more LEDs configured to provide white light having a CCT of about 6500K. The neutral white light source via the third LED group 494C may include one or more LEDs configured to provide light having a CCT of about 4000K. Although various white LEDs are described in this example, one of ordinary skill in the art will recognize that other color combinations consistent with the embodiments described herein are possible to provide composite light output from the LED array 491 in various overall colors.

The power module 452 may include a dimmable engine (not shown) that may be configured to power the LED array 491 through three separate channels (represented in fig. 11E as LED1+, LED2+, and LED3 +). More specifically, the dimmable engine may be configured to supply a first PWM signal to a first LED group 494A, e.g., a warm white light source, via a first channel, a second PWM signal to a second LED group 494B group via a second channel, and a third PWM signal to a third LED group 494C via a third channel. Each signal provided via a respective channel may be used to power a corresponding LED or group of LEDs, and the duty cycle of the signal may determine the total duration of the on and off state of each respective LED. The duration of the on and off states may result in an overall light effect, which may have light properties (e.g. Correlated Color Temperature (CCT), color point or brightness) based on the duration. In operation, the dimmable engine may change the relative amplitudes of the duty cycles of the first, second and third signals to adjust the respective light characteristics of each LED group to provide composite light having the desired emission from the LED array 491. As described above, the light output of the LED array 491 may have a color point that is based on a combination (e.g., a mixture) of the light emissions from each of the

LED groups

494A, 494B, and 494C.

In operation, the power module 452 may receive control inputs generated based on user and/or sensor inputs and provide signals via the various channels to control the composite color of light output by the LED array 491 based on the control inputs. In some embodiments, a user may provide input to the LED system to control the DC/DC converter circuit by turning a knob or moving a slider, which may be part of a sensor module (not shown), for example. Additionally or alternatively, in some embodiments, a user may use a smartphone and/or other electronic device to provide input to the LED lighting system 400D to send an indication of a desired color to a wireless module (not shown).

Fig. 12 shows an example system 550 that includes an application platform 560, LED lighting systems 552 and 556, and

secondary optics

554 and 558. LED lighting system 552 generates a light beam 561 shown between

arrows

561a and 561 b. LED lighting system 556 may produce a beam 562 between

arrows

562a and 562 b. In the embodiment shown in fig. 12, light emitted from LED lighting system 552 passes through secondary optic 554, and light emitted from LED lighting system 556 passes through secondary optic 558. In an alternative embodiment,

light beams

561 and 562 do not pass through any secondary optics. The secondary optic may be or may include one or more light guides. The one or more light guides may be edge-lit or may have an interior opening defining an interior edge of the light guide. The LED illumination systems 552 and/or 556 may be inserted into the interior opening of the one or more light guides such that they inject light into the inner edge (interior opening light guide) or the outer edge (edge emitting light guide) of the one or more light guides. The LEDs in LED lighting systems 552 and/or 556 can be arranged around the circumference of a base that is part of a light guide. According to an embodiment, the base may be thermally conductive. According to an embodiment, the base may be coupled to a heat dissipating element disposed above the light guide. The heat dissipating element may be arranged to receive heat generated by the LED via the thermally conductive base and dissipate the received heat. The one or more light guides can allow the light emitted by the LED illumination systems 552 and 556 to be shaped in a desired manner, e.g., with a gradient, a chamfered distribution, a narrow distribution, a wide distribution, an angular distribution, etc.

In an example embodiment, the system 550 may be a mobile phone of a camera flash system, indoor residential or commercial lighting, outdoor lighting such as street lighting, automobiles, medical devices, AR/VR devices, and robotic devices. The integrated LED lighting system 400A shown in fig. 11A, the integrated LED lighting system 400B shown in fig. 11B, the LED lighting system 400C shown in fig. 11C, and the LED lighting system 400D shown in fig. 11D illustrate LED lighting systems 552 and 556 in example embodiments.

The application platform 560 may provide power to the LED lighting systems 552 and/or 556 via a power bus or other applicable input of line 565, as discussed herein. Further, application platform 560 may provide input signals for operation of LED lighting system 552 and LED lighting system 556 via line 565, which may be based on user input/preferences, sensed readings, preprogrammed or autonomously determined outputs, and the like. The one or more sensors may be internal or external to the housing of the application platform 560.

In various embodiments, the application platform 560 sensors and/or the LED lighting systems 552 and/or 556 sensors may collect data, such as visual data (e.g., LIDAR data, IR data, data collected via a camera, etc.), audio data, distance-based data, movement data, environmental data, and the like, or combinations thereof. The data may relate to physical items or entities such as items, people, vehicles, etc. For example, the sensing device may collect object proximity data for ADAS/AV based applications, which may prioritize detection and subsequent actions based on detection of physical items or entities. Data may be collected based on light signals, such as IR signals, emitted by, for example, LED lighting systems 552 and/or 556, and data collected based on the emitted light signals. Data may be collected by a component different from the component that emits the optical signal used for data collection. Continuing with this example, the sensing device may be located on an automobile and may emit a light beam using a Vertical Cavity Surface Emitting Laser (VCSEL). One or more sensors may sense a response to the emitted light beam or any other suitable input.

In an example embodiment, application platform 560 may represent an automobile, and LED lighting system 552 and LED lighting system 556 may represent automobile headlights. In various embodiments, the system 550 may represent an automobile with a steerable light beam, where the LEDs may be selectively activated to provide steerable light. For example, an array of LEDs may be used to define or project a shape or pattern, or to illuminate only selected portions of a roadway. In an example embodiment, infrared camera or detector pixels within LED lighting systems 552 and/or 556 may be sensors that identify portions of a scene (road, pedestrian crossing, etc.) that need to be illuminated.

Fig. 13A is a diagram of an LED device 200 in an example embodiment. LED device 200 may include a substrate 202, an active layer 204, a wavelength converting layer 206, and a primary optic 208. In other embodiments, the LED device may not include a wavelength converting layer and/or a primary optic. The single LED device 200 may be included in an LED array in an LED lighting system, such as any of the LED lighting systems described above.

As shown in fig. 13A, the active layer 204 may be adjacent to the substrate 202 and emit light when excited. Suitable materials for forming the substrate 202 and active layer 204 include sapphire, SiC, GaN, silicone, and more particularly may be formed from III-V semiconductors including, but not limited to, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, II-VI semiconductors including, but not limited to, ZnS, ZnSe, CdSe, CdTe, group IV semiconductors including, but not limited to, Ge, Si, SiC, and mixtures or alloys thereof.

The wavelength conversion layer 206 may be remote from, proximate to, or directly above the active layer 204. Active layer 204 emits light into wavelength-converting layer 206. Wavelength-converting layer 206 is used to further modify the wavelength of light emitted by active layer 204. LED devices that include a wavelength conversion layer are commonly referred to as phosphor converted LEDs ("PCLEDs"). The wavelength conversion layer 206 may comprise any luminescent material, such as phosphor particles in a transparent or translucent binder or matrix, or ceramic phosphor elements that absorb light of one wavelength and emit light of a different wavelength.

The primary optic 208 may be on or over one or more layers of the LED device 200 and allows light from the active layer 204 and/or the wavelength conversion layer 206 to pass through the primary optic 208. The primary optic 208 may be a lens or an encapsulation device configured to protect one or more layers and at least partially shape the output of the LED device 200. The primary optic 208 may include a transparent and/or translucent material. In an example embodiment, the light via the primary optic may be emitted based on a Lambertian distribution pattern. It should be appreciated that one or more characteristics of the primary optic 208 may be modified to produce a light distribution pattern that is different from a lambertian distribution pattern.

Fig. 13B shows a cross-sectional view of an illumination system 220 including an LED array 210 having

pixels

201A, 201B, and 201C and a secondary optic 212 in an example embodiment. The LED array 210 includes

pixels

201A, 201B, and 201C, each including a respective wavelength converting layer 206B, active layer 204B, and substrate 202B. The LED array 210 may be a monolithic LED array fabricated using wafer-level processing techniques, micro-LEDs having sub-500 micron dimensions, or the like.

Pixels

201A, 201B, and 201C in LED array 210 may be formed using array segmentation or alternatively using pick and place techniques.

The space 203 shown between one or

more pixels

201A, 201B, and 201C of the LED device 200B may include an air gap or may be filled with a material, such as a metallic material, which may be a contact (e.g., an n-contact).

Secondary optic 212 may include one or both of lens 209 and waveguide 207. It should be appreciated that although secondary optics are discussed in accordance with the illustrated example, in an example embodiment, secondary optics 212 may be used to spread incident light (diverging optics) or to concentrate incident light into a collimated beam (collimating optics). In an example embodiment, the waveguide 207 may be a concentrator and may have any suitable shape for concentrating light, such as a parabolic shape, a conical shape, a beveled shape, and the like. Waveguide 207 may be coated with a dielectric material, a metallization layer, or the like for reflecting or redirecting incident light. In alternative embodiments, the lighting system may not include one or more of the following: conversion layer 206B, primary optic 208B, waveguide 207, and lens 209.

The lens 209 may be formed of any applicable transparent material, such as, but not limited to, SiC, alumina, diamond, and the like, or combinations thereof. The lens 209 may be used to modify the light beam input into the lens 209 so that the output beam from the lens 209 will effectively meet the desired photometric specifications. Additionally, the lens 209 may be used for one or more aesthetic purposes, for example, by determining the lit and/or unlit appearance of the

LED devices

201A, 201B, and/or 201C of the LED array 210.

Having described embodiments in detail, those skilled in the art will appreciate that given the present description, modifications may be made to the embodiments described herein without departing from the spirit of the inventive concept. Therefore, the scope of the invention is not limited to the specific embodiments shown and described.

Claims

1. An apparatus, comprising:

a dimmer switch interface, the dimmer switch interface comprising:

(i) a transformer having a first winding magnetically coupled to a second winding, the first winding being electrically coupled to a pair of terminals; and

(ii) a current source configured to provide an intermittent alternating current to the second winding, the intermittent alternating current having a periodic waveform, each period of the waveform including a first portion during which the current is fixed at a predetermined fixed low value and a second portion during which the current alternates between a high value and a low value.

2. The apparatus of claim 1, wherein the transformer is intermittently switched on and off as a result of being powered with intermittent alternating current.

3. The apparatus of claim 1, wherein a duration of a first portion of any cycle is longer than a duration of a second portion of the same cycle.

4. The apparatus of claim 1, wherein the current source is configured to provide intermittent alternating current to the transformer only when the dimmer switch is in a standby mode, the standby mode being a mode in which the dimmer switch at least partially generates the voltage signal having a value that falls within a predetermined range.

5. The apparatus of claim 1, wherein the dimmer switch interface further comprises a control circuit arranged to receive a signal through the pair of terminals for connecting the dimmer switch interface to the dimmer switch, the control circuit configured to:

when the signal has a first value, causing the current source to provide intermittent alternating current to the transformer; and

when the signal has a second value, the current source is caused to provide a continuous alternating current to the transformer.

6. The apparatus of claim 1, wherein an intermittent alternating current duty cycle of about 10% reduces power consumption by at least 80%.

7. A system, comprising:

a dimmer switch; and

a dimmer switch interface coupled to the dimmer switch, the dimmer switch interface comprising:

(i) a transformer having a first winding magnetically coupled to a second winding, the first winding electrically coupled to the dimmer switch; and

(ii) a current source configured to provide an intermittent alternating current to the second winding, the intermittent alternating current having a periodic waveform, each period of the waveform including a first portion during which the intermittent alternating current is fixed at a predetermined fixed low value and a second portion during which the intermittent alternating current alternates between a high value and a low value.

8. The system of claim 7, wherein the transformer is intermittently switched on and off as a result of being powered with intermittent alternating current.

9. The system of claim 7, wherein the duration of the first portion of any cycle is longer than the duration of the second portion of the same cycle.

10. The system of claim 7, wherein the current source is configured to provide intermittent alternating current to the transformer only when the dimmer switch is in a standby mode, the standby mode being a mode in which the dimmer switch generates a voltage signal that causes a driver of the light fixture to turn off a light source of the light fixture.

11. The system of claim 7, wherein the dimmer switch interface further comprises a control circuit arranged to receive a signal generated at least in part by the dimmer switch, the control circuit configured to:

12. The system of claim 7, wherein an intermittent alternating current duty cycle of about 10% reduces power consumption by at least 80%.

13. A system, comprising:

a light fixture comprising a driver coupled to a light source; and

a dimmer switch coupled to the driver via a dimmer switch interface, the dimmer switch interface comprising:

(i) a transformer having a first winding magnetically coupled to a second winding, the first winding electrically coupled to the dimmer switch, and the second winding electrically coupled to a driver of the light fixture; and

14. The system of claim 13, wherein the transformer is intermittently switched on and off as a result of being powered with intermittent alternating current.

15. The system of claim 13, wherein the duration of the first portion of any cycle is longer than the duration of the second portion of the same cycle.

16. The system of claim 13, wherein the current source is configured to provide intermittent alternating current to the transformer only when the dimmer switch is in a standby mode, the standby mode being a mode in which the dimmer switch generates a voltage signal that causes a driver of the light fixture to turn off a light source of the light fixture.

17. The system of claim 13, wherein the dimmer switch interface further comprises a control circuit arranged to receive a signal generated at least in part by the dimmer switch, the control circuit configured to:

18. The system of claim 13, wherein an intermittent alternating current duty cycle of about 10% reduces power consumption by at least 80%.

19. A method, comprising:

detecting a voltage level of the DIM signal;

determining whether the dimmer switch is in a standby mode;

supplying an intermittent alternating current to the transformer if it is determined that the dimmer switch is in the standby mode; and

if it is determined that the dimmer switch is not in the standby mode, a continuous current is supplied to the transformer.

20. The method of claim 19, wherein the intermittent alternating current comprises a periodic waveform, each period of the waveform comprising a first portion during which the intermittent alternating current is fixed at a predetermined fixed low value and a second portion during which the intermittent alternating current alternates between a high value and a low value.